Paper-insulated conductor



June 10, 1930. E. B. woo'o PAPER INSULATED CONDUCTOR Filed May 29, 19262 Sheets-Sheet 1 'IIIIIIIIIII/I/IIl/l/III June 10, 1930. E, 3 9011,762,941

PAPER INSULATED CONDUCTOR Filed May 29, 1926 2 Sheets-Sheet 2 five/7hr.-frnes? 5; Wood Fatented June 1'0, 1930 UNITED s'rArEs PATENT; oFncr.

' 3. W001), or cnarrrul, n'nw msnv, assrenon. T BELL 'rnmrnom mozwroams,mcoaroaa'rm, or mrw roux, n. Y., A conronarron or nnw YoaxYAPEB-INSULATH) CONDUCTOR Application fled Kay 29, 1928. Serial 1T0.112,532.

This invention relates to pa r insulated conductors and a method of m'ng them.

An object of this invention is an inexpensive, substantiallymoisture-proof paper insulated conductor capable of withstanding severeservice strains.

The method of applying the paper insulation to the conducting core does'not form a part of this invention since the method used is thatdisclosed in the copendin a plication of H. G. Walker and A. T. Marci,547,924, filed March 29, 1922, Patent No. 1,615 417 dated Jan. 25, 1927.The moistureproofing or impregnating process also is disclosed in thecopending ap lication of D. R. gr2o5bst, SerialNo. 68,058, ed November10,

The conductor of this invention has its insulation reinforced by theapplication of a serving of yarn which partially embeds itself in thesomewhat moist paper coating, previous to the moisture-proofing byimpregnating with cellulose acetate lacquer.

The invention will be better understood from the following descriptiontogether withthe attached drawings forming a part thereof and in which,

Fig. l is a diagrammatic representation of the apparatus required forcoating and impregnating the conductor;

ig. 2 is a top view on an enlarged scale of a art of the pulp applyingapparatus;

ig. 3 is a side view of the pulp former;

Fig. 4 is a section of the same on line 44 of Fig. 3;

Fig. 5 is a view in section of a part of the squeezing roll;.

Fig. 6 is a view in section of a part of the main drum;

- Figs. 7, 8, 9 and 10 represent different stepsin the formation of thepulp on the conductor; and Fig. 11 is a side view of the insulatedconductor.

Referring now garticularly to Fig. 1, the core 74 to be coate is fedfrom a supply reel 20, over an idler roll 21 and-thence around a drum 22which is partly submerged in liquid containing ulp within asemi-spherical trough 23. e drum 22 comprises a pair of sheet metalsides 24, 6) and a peripheral erial Nothe tank 23, as indicated byportion 25 secured thereto. The portion 25 is provided with a pluralityof relatively large perforations 26 which are covered with a narrowstrip of fine wire mesh 27. The core, in passing around the .drum, liesupon the wire mesh 27 The drum 22 has a centrally disposed tubular axle28 which is rotatably mounted in suitable bearings 29 carried by aframework 30 which supports all the elements ofthe a paratus.

In or or to apply pulp to the core as it passes overthe drum 22, the.pulp mixture within the drum is maintained at a lower level than that ofthe level of the pulp mixture in dottedlines A and B, respectively. Thisdifference in levels is maintained by a siphon pipe 31 which has itsinlet opening submerged in the pulp mixture within the drum 22 and itsdischarge through the tubular axle 28. A continuous back into the suppltank 32, in any suitable manner. As the rum 22 carries the core thereonthrough the tank, the liquid in tank 23 will pass through the wire mesh27 and perforations 26, due to the difference in levels of liquid withinthe drum and the tank 23 straining the pulp onto the outersurface o thewire mesh and applying the pul' to the core supported thereon. In orderto E e the wire mesh clean prior to its reception 0 the core, and a newcoating of pulp, it is washed by a jet of water, under pressure, whichis su i plhedthrough a nozzle 33.

e drum 22 is rotated in the direction indicated b the arrow. The core74, with a coating 0 pulp thereon, leaves the drum at the top thereofand the force of gravity, the surface tension of the liquid in the pulpmixture, and the felting of the pulp fibres cause the pulp to surroundthe'core andv clin to it mounted between a pair of brackets 37 securedto an upright standard 38 supported by the framework 30. The shaftcarrying the roll 36 is driven through a pulley attached thereto whichis actuated by a motor 39 in any suitable manner, as by means of belts40 and 41. The core is drawn from the supply reel 20 over the drum 22,causing it to rotate, by the squeezing rolls and 36. 1.

The auxiliary roll-34, as shown in Fig. 5, is a hollow sheet metal drumhaving a pcripheral slot covered with a strip of fine wire mesh 42. Ithas been found preferable to employ the auxiliary roll 34 and to make itforaminous where it engages the core and pulp coating thereon in orderthat the free liquid, so to speak,mav bestrained ofi away from the coreand coating. If such a roll were not provided, the excess liquid wouldtend to wash ofi the pulp coating, since at this stage the ulp coatingis very soft and easily removed from the core. With the free liquidremoved, the coating has greater strength due to a closer felting of thefibres so that when the core and coating are passed through thesqueezing rolls, the coating will not be torn from the core.

The squeezing rolls ma be formed of rubher and forced together y anysuitable adjustable means to place the proper pressure on the core andpul coating as they pass between the rolls.

ese rolls remove the greater rtion of liquid from the pulp mixture anform the ulp into a thin ribbon which extends latera y from each side ofthe core as shown in Fig. 8. This squeezing operation also mats or feltsthe fibres into more intimate relation thereby increasing theafter theforming action is completed isv shown in Fi 9 and 10. The former causesa thorou h mtermingling of the pulp fibres and mol the coating toconform to the shape of the core. 6

The former, shown in detail in Figs. 3 and 4, comprises two on -shapedcollars 43 and 44 hel together an in spaced relation by means of rods45. Integral with said collars 43 and 44 are sleeves 46 and 46'respectively, which are rotatably mounted-within suitable bearings inthe standards 38 and another pair of standards 47 supported by theframework 30. Two plates 48 and 49 have projecting tongues which arebent around two of the rods 45 to pivotally support the rcilates inopposed relation to eac other.

ompression s rings 50 engage the rear faces of plates 48 an 49 and tento force them to,-

gether. The springs 50 are put under the requisite compression by meansof adjusting screws 51 which are mounted in brackets 52 secured to therods 45. The ends of the plates 48 and 49, adjacent the squeezing rolls35 and 36, are flared outwardly so as to present a smooth surface to thecore and pulp coating as they pass from these rolls through the sleeve46 and between the forming lates 48 and 49. The core passes from theorming plates through the sleeve 46.

The plates 48 and 49 are rapidly rotated around the core having the pulpcoating thereon, through the medium of a pulley 18 secured to the sleeve46, the pulley being driven by the motor 39 through a belt 17.

The forming plates 48 and 49 wrap the projecting edges of the pulpribbon about each other and around the core in much the same manner asthough the core and pulp ribbon were rolled on a tabletop with the palmof the hand.

As the coated core leaves the former, a serving-head 55 wra s a layer ofyarn 76 over the pul coating. ince the pulp coating is still so andmoist this yarn as shown in Fig. 11 will partially embed itself in thecoating thereby greatly strengthening it. This yarn may be of anysuitable material and of any convenient size and is served so that thereis no overlapping or portions of unprotected pulp coating. The servingusually consists of about seven or nine strands.

If desired, strands of distinct colors may be introduced into the yarnto act as markers.

The core with its formed coating passes from the serving-head to amechanism for drying out the coating. The means shown for this operationis a pair of wide hollow drums 52 and 53 heated internally and having aplurality of grooves 53 formed thereon (Fig. 2) which receive the core.Guides (not shown) are provided for drawing the core over first one drumand then the other until the coated core has traversed all of thegrooves on both drums, after which it is drawn over a suitable pulley orother guiding means 3 to an impregnating tank 4 containing a celluloseacetate bath 5. The impregnatin tank 4 is preferably composed of a suitale electrically conducting, cellu-' lose acetate-inert material such,for example, as brax.

From the pulley 3, the conductor passes under pulley 6, up and overpulley'7, down and under pulley 8, up and out of thebath and tank andover pulley 9. From the tank 4 the conductor passes to a secondimpregnating tank 10 and drying chamber 11 and then to a suitabletake-up reel 12.

The'take-up reel 12 is'preferably formed of an electrically conductingmaterial so that it may be employed as one of the electrodes forapplying potential between the conductor and the bath containing theconductor during the impregnation treatment. When used 1n this manner,the conductin core of the conductor being treated is attac ed to themetallic core of the take-up reel 12. A suitable binding post isattached to the impregnating chamber 4 such as shown at 13.

During the passage of the conductor throu h the impregnating tank 4, apotential is applied, as set forth in the above mentioned Brobstapplication, between suitable electrodes, such as the metallic reel 12,to which the conducting core of the conductor is electrically attached,and the binding post 13; the reel 12, being preferably made the anode orpositive electrode. With the application of such a potential between theconductor and the container holding the conductor durin the impregnatingtreatment, it has been foun that the cellulose acetate solutionpenetrates finish is produced if the conductor is passed through aplurality of additional impregnation ste s without the application of apotential. herefore after leaving the tank 4, the conductor is drawnunder a suitable guide pulley 14 and through a cellulose acetate bath 15contained in the tank 10. The distance traveled by the conductor afterleaving tank 4 and before entering the bath 15 should be so short thatthere will be no deposition of moisture on the conductor.

The conductor then passes through the drying chamber 11 which may be,for example, an electric furnace comprising a refractory core wound withsuitable resistance wire 71 and enclosed within a second refractory tube72 over which suitable heat insulating material 7 3 is placed.

The insulation of the conductor after passing through the chamber 11should be thoroughly dry. This may be accomplished by maintaining a hightem rature 1n the furnace or by giving the con uctor several passes inthe furnace.

What is claimed is:

1. An electrical conductor comprising a metallic core, a coating ofloose fibrous material thereon and a layer of textile material enclosingsaid fibrous material coating, said coating and said layer of textilematerial being impregnated with cellulose acetate.

2. An electrical .conductor comprising a conducting core, a coating ofpaper pulp thereon and a serving of yarn enclosing said coating, saidcoating and said serving being impregnated with cellulose acetate.

3. An electrical conductor comprising a conducting core, a coatingofpaper pulp thereon and a layer of textile material en- 70 closing saidpaper pulp and partially embedded therein, said pulp and said layer oftextile material being impregnated with cellulose acetate.

4. An electrical conductor comprising a conducting core, a coating ofpaper pulp thereon and a serving of cotton arn enclosing said pulp andpartially embedded therein, said coating and said serving beingimpregnated with cellulose acetate.

5. A method of coating 9. core which consists in applying wet pulp tothe core and causing it to con orm to the shape of the core, enclosingsaid pulp, while moist, with a serving of textile material, drying saidpulp and textile material, impregnating said pulp. and said textilematerial with cellulose acetate and again drying the combined corecovering.

6. A method of coating a' core which consists in applying wet pulptheretoand molding it to conform to the shape of the corei wrapping aserving comprising a plurality o strands of textile material around saidulp with sufiicient force to cause the strand; to be partially embeddedtherein, drying the pulp and textile material, impregnating said pulpand strands with cellulose acetate and again drying the combined corecovering.

7. A method of insulating an electrical conductor which consists inapplying wet paper pulp' to the conductor core and molding the pulp toconform to the shape of the core, wrapping a serving comprising aplurality of strands of cotton yarn around the pulp, while it is stillmoist, with sulficient force to cause the strands to be partiallyembedded therein, drying the pulp and yarn, subjecting the conductor andcovering to a bath of cellulose acetate while maintainin a potentialdifi'erence between the bath and t e core and thoroughly dr ing thecombined core covering.

n witness whereof, I hereunto subscribe my name this 25th da of May, A.D. 1926.

E NEST B. WOOD. 11s

